Adds some possible NULL references and small fixes

fluid/Fl_Grid_Type.cxx

@@ -187,7 +187,11 @@ Fl_Grid::Cell* Fl_Grid_Proxy::transient_widget(Fl_Widget *wi, int row, int col,
     int mw, mh;
     old_cell->minimum_size(&mw, &mh);
     new_cell->minimum_size(mw, mh);
-    ::free(old_cell);
+    if (remove_old_cell) {
+      remove_cell(old_cell->row(), old_cell->col());
+    } else {
+      delete old_cell;
+    }
   }
   if (i == num_transient_) {
     transient_make_room_(num_transient_ + 1);
@@ -195,9 +199,6 @@ Fl_Grid::Cell* Fl_Grid_Proxy::transient_widget(Fl_Widget *wi, int row, int col,
     num_transient_++;
   }
   transient_[i].cell = new_cell;
-  if (remove_old_cell) {
-    remove_cell(old_cell->row(), old_cell->col());
-  }
   return new_cell;
 }
 
@@ -911,12 +912,12 @@ void grid_align_horizontal_cb(Fl_Choice* i, void* v) {
     Fl_Grid::Cell *cell = g->cell(current_widget->o);
     if (cell) {
       old_v = cell->align() & mask;
-    }
-    if (old_v != v) {
-      cell->align((Fl_Grid_Align)(v | (cell->align() & ~mask)));
-      g->need_layout(true);
-      g->redraw();
-      set_modflag(1);
+      if (old_v != v) {
+        cell->align((Fl_Grid_Align)(v | (cell->align() & ~mask)));
+        g->need_layout(true);
+        g->redraw();
+        set_modflag(1);
+      }
     }
   }
 }
@@ -946,12 +947,12 @@ void grid_align_vertical_cb(Fl_Choice* i, void* v) {
     Fl_Grid::Cell *cell = g->cell(current_widget->o);
     if (cell) {
       old_v = cell->align() & mask;
-    }
-    if (old_v != v) {
-      cell->align((Fl_Grid_Align)(v | (cell->align() & ~mask)));
-      g->need_layout(true);
-      g->redraw();
-      set_modflag(1);
+      if (old_v != v) {
+        cell->align((Fl_Grid_Align)(v | (cell->align() & ~mask)));
+        g->need_layout(true);
+        g->redraw();
+        set_modflag(1);
+      }
     }
   }
 }

fluid/Fl_Widget_Type.cxx

@@ -3659,9 +3659,9 @@ void Fl_Widget_Type::copy_properties() {
   if (!live_widget)
     return;
 
-  Fl_Font ff;
-  int fs;
-  Fl_Color fc;
+  Fl_Font ff = 0;
+  int fs = 0;
+  Fl_Color fc = 0;
   textstuff(0, ff, fs, fc);
 
   // copy all attributes common to all widget types

fluid/factory.cxx

@@ -1243,7 +1243,8 @@ Fl_Type *add_new_widget_from_user(Fl_Type *inPrototype, Strategy strategy) {
       if (changed && t->is_a(ID_Menu_Item)) {
         Fl_Type * tt = t->parent;
         while (tt && !tt->is_a(ID_Menu_Manager_)) tt = tt->parent;
-        ((Fl_Menu_Manager_Type*)tt)->build_menu();
+        if (tt)
+          ((Fl_Menu_Manager_Type*)tt)->build_menu();
       }
     }
     if (t->is_true_widget() && !t->is_a(ID_Window)) {

fluid/shell_command.cxx

@@ -795,7 +795,7 @@ void Fd_Shell_Command_List::write(Fd_Project_Writer *out) {
 void Fd_Shell_Command_List::add(Fd_Shell_Command *cmd) {
   if (list_size == list_capacity) {
     list_capacity += 16;
-    list = (Fd_Shell_Command**)::realloc(list, list_capacity * sizeof(Fd_Shell_Command**));
+    list = (Fd_Shell_Command**)::realloc(list, list_capacity * sizeof(Fd_Shell_Command*));
   }
   list[list_size++] = cmd;
 }
@@ -809,7 +809,7 @@ void Fd_Shell_Command_List::add(Fd_Shell_Command *cmd) {
 void Fd_Shell_Command_List::insert(int index, Fd_Shell_Command *cmd) {
   if (list_size == list_capacity) {
     list_capacity += 16;
-    list = (Fd_Shell_Command**)::realloc(list, list_capacity * sizeof(Fd_Shell_Command**));
+    list = (Fd_Shell_Command**)::realloc(list, list_capacity * sizeof(Fd_Shell_Command*));
   }
   ::memmove(list+index+1, list+index, (list_size-index)*sizeof(Fd_Shell_Command**));
   list_size++;

src/Fl_String.cxx

@@ -137,7 +137,8 @@ Fl_String &Fl_String::replace_(int at, int n_del, const char *ins, int n_ins) {
     ::memmove(buffer_+at, ins, n_ins);
   }
   size_ = new_size;
-  buffer_[size_] = 0;
+  if (buffer_)
+    buffer_[size_] = 0;
   return *this;
 }
 

src/Fl_Text_Buffer.cxx

@@ -1406,11 +1406,11 @@ int Fl_Text_Buffer::insert_(int pos, const char *text, int insertedLength)
 /*
  Remove a string from the buffer.
  Unicode safe. Start and end must be at a character boundary.
+ Start must be less than end.
  */
 void Fl_Text_Buffer::remove_(int start, int end)
 {
-  /* if the gap is not contiguous to the area to remove, move it there */
-
+  if (start >= end) return;
   if (mCanUndo) {
     if (mUndo->undoat == end && mUndo->undocut) {
       // continue to remove text at the same cursor position